In the past, the suitability of Er for Si-based light emission was already investigated in detail. However, much less attention has been paid to Nd with its main electroluminescence (EL) line around 900 nm. In this study we compare the electrical and EL properties of Er- and Nd-implanted metal-oxide-semiconductor (MOS) structures where the dielectric stack is composed of the implanted SiO2 layer and a SiON buffer layer. Regarding the EL, the EL spectrum, the EL decay time and the EL efficiency were measured. The electrical characterization comprises current-voltage and capacitance-voltage measurements. Although the EL efficiency of Nd-implanted devices is by a factor of 5 to 10 lower than that of Er-based, the emission wavelength of Nd has some advantages compared to that of Er. Finally, based on these results the suitability of these two types of light emitters for integrated photonic devices is discussed.